diff --git a/3-99 Research/Haskell/baby.hs b/3-99 Research/Haskell/baby.hs
index 2b7e6cd2..821dcc81 100644
--- a/3-99 Research/Haskell/baby.hs	
+++ b/3-99 Research/Haskell/baby.hs	
@@ -14,3 +14,7 @@ boomBangs xs = [ if x< 10 then "BOOM!" else "BANG!" | x <- xs, odd x]
 
 schtankyList x = [ x*y | x <- [2,5,10], y <- [8,10,11]]
 
+-- Now Writing our own custom list function
+length' xs = sum [1 | _ <- xs] 
+-- use dummy variable _, draw an element from a list and replace it with 1. Sum all of those.
+